Can I file more than one person't return using Turbotax Premier?

Are you using the Desktop version?

Online is only good for 1 return.  But you can use the same email address for 5 accounts.   How to start another return in the Online version https://ttlc.intuit.com/replies/3288574 

Yes, if you are using the Desktop version, you can prepare and e-file up to 5 Federal Tax Returns. 

If you are using the Online version, you can only prepare one Tax Return per account.